Transformer with DC Supply – Rankers Physics

Transformers: Practice Problem & Solution

Assertion (A): If we use a battery across the primary of a step up transformer, no voltage is obtained across secondary. Reason (R): Battery gives a steady current.  
Both (A) & (R) are true and the (R) is the correct explanation of the (A)
Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(A) is true but (R) is false
Both (A) and (R) are false

Short Solution (Best for NEET):

To solve this problem, we apply the core principles of Transformers. Understanding the underlying formula is key to arriving at the correct answer below:

Assertion (A) is true. Transformers require a changing magnetic flux to induce voltage. Reason (R) is true; a battery provides DC current. This steady current causes constant flux, hence no induced emf in the secondary. (R) correctly explains (A).

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